Frontend Login and Registration Blocks <= 1.1.1 - Unauthenticated Privilege Escalation via Account Takeover
Strategic Overview
- Status
- Patched in 1.2.0
- Affected Plugin
- Login, Registration and Lost Password Blocks
- Affected Version
<= 1.1.1- CVSS
- 9.8Critical
- Weakness type
- CWE-639 · Authorization Bypass Through User-Controlled Key
- CVE
CVE-2025-3605
At a glance
CVE-2025-3605 is a critical-severity Authorization Bypass Through User-Controlled Key vulnerability in the Login, Registration and Lost Password Blocks WordPress plugin, affecting versions <= 1.1.1. It carries a CVSS score of 9.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires no authentication. The issue is fixed in version 1.2.0; sites on affected versions should update now. Disclosed May 2025, reported by kr0d.
Vulnerability Overview
The Frontend Login and Registration Blocks plugin for WordPress is vulnerable to privilege escalation via account takeover in all versions up to, and including, 1.1.1. This is due to the plugin not properly validating a user's identity prior to updating their details like email via the flr_blocks_user_settings_handle_ajax_callback() function. This makes it possible for unauthenticated attackers to change arbitrary user's email addresses, including administrators, and leverage that to reset the user's password and gain access to their account.
Technical Analysis
The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site, and no interaction from a victim user. A successful exploit has high impact on confidentiality, integrity, availability — full site compromise territory.
CWE-639: Authorization Bypass Through User-Controlled Key
Login, Registration and Lost Password Blocks <= 1.1.1 carries this weakness at flr_blocks_user_settings_handle_ajax_callback(), and reaching it takes no account at all. Authorization bypass through a user-controlled key, often called insecure direct object reference, means the application looks up a record by an identifier from the request without checking that the caller owns it.
Changing a number in the request is enough to read or modify other users' records, which on commerce and membership sites means customer data. For Login, Registration and Lost Password Blocks the fix is 1.2.0: builds <= 1.1.1 are affected, anything from 1.2.0 onward is not.
Remediation
Update to version 1.2.0, or a newer patched version
How does WordSec protect against this?
This one needs no account at all, which puts it outside what login hardening can reach; WordSec's login security narrows the account-level paths around it, and the firewall is what inspects the request itself. None of that substitutes for the fix: Login, Registration and Lost Password Blocks 1.2.0 closes this, and updating the plugin is the step that ends it.
- Login Security
- Alerts
External References
Related records
Other vulnerabilities in Login, Registration and Lost Password Blocks
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